Chris Koster waited only three months into Gov. Jay Nixon’s second term to announce that he was preparing a run for Missouri governor in 2016.

The two-term attorney general has coasted on a smooth-as-glass highway to the Democratic nomination ever since.

Until now.

In recent days, two longtime party leaders — former lieutenant governor Joe Maxwell and former state senator Joan Bray — have questioned Koster’s bona fides for the state’s highest office.

Their concerns center on recent Koster moves that they say cloud his commitment to the Democratic Party he joined almost exactly seven years ago in a switch that stunned politicos.

That Bray is a liberal serves to highlight the long-standing tensions between Democratic conservatives and progressives in a party increasingly centered in the state’s two biggest cities.

Bray and Maxwell, known for his work on elderly and children’s issues, pointed to Koster’s public support of the controversial “right to farm” amendment that appears to have narrowly passed. Critics, including Maxwell, called the amendment a sellout to corporate and foreign interests.

Koster backed the “right to bear arms” amendment that passed with National Rifle Association backing but that many Democrats opposed. Koster has long enjoyed NRA support.

Some Democrats are piqued by the $260,000 campaign donation that Koster accepted from GOP kingmaker Rex Sinquefield. And Bray had hoped that Koster would oppose the 3/4-cent sales tax for highways based on the hit the state’s poorest citizens would have taken. Instead, Koster took no position.

“I have questions about where he’s coming from,” Bray said.

Said Maxwell: “Who is the real Chris Koster? These moves are concerning to Democrats who don’t know him that well.”

That Koster has run so free of intraparty competition has allowed him to shift right and back the gun and farm amendments. But Maxwell said it was too soon to make that move given that Koster hasn’t been a Democrat all that long.

Koster is Democratic in other ways. He backs stem cell research. He supports abortion rights, has strong labor credentials and favors Medicaid expansion, Common Core education standards and higher school funding.

Maxwell and Bray aren’t saying no to Koster. Neither are they saying yes.

Maxwell didn’t rule out a possible political comeback — and his own run for governor in 2016.